The toy companies that I work with are very good at making sure they aren't stuck with stock, and the retailers are.
They'll create the demand, and yet not have the stock available. You ask them when the stock will be in, and they'll give a future date with pre-orders accepted only.
So all the retailers panic, and place their large orders, believing they will be popular.
Toy company have pre-sold everything they have coming in, and it's down to the retailers to sell or not.
Plus their trade prices are shocking. There isn't the margin that you think there is.
With the eBayers, I guess they are one off sales. They're not going to be millionaires from it.
The real issue does lie with the toy manufacturers.
In general the real issues lie with the fat cats, and not Mrs Jones who made £30 profit off a popular toy.